| /* |
| * Copyright (C) 2014-2016 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef _ANDROID_UTILS_FASTSTRCMP_H__ |
| #define _ANDROID_UTILS_FASTSTRCMP_H__ |
| |
| #ifdef __cplusplus |
| |
| // Optimized for instruction cache locality |
| // |
| // Template class fastcmp used to create more time-efficient str*cmp |
| // functions by pre-checking the first character before resorting |
| // to calling the underlying string function. Profiled with a |
| // measurable speedup when used in hot code. Usage is of the form: |
| // |
| // fastcmp<strncmp>(str1, str2, len) |
| // |
| // NB: Does not work for the case insensitive str*cmp functions. |
| // NB: Returns boolean, do not use if expecting to check negative value. |
| // Thus not semantically identical to the expected function behavior. |
| |
| template <int (*cmp)(const char *l, const char *r, const size_t s)> |
| static inline int fastcmp(const char *l, const char *r, const size_t s) { |
| return (*l != *r) || cmp(l + 1, r + 1, s - 1); |
| } |
| |
| template <int (*cmp)(const void *l, const void *r, const size_t s)> |
| static inline int fastcmp(const void *lv, const void *rv, const size_t s) { |
| const char *l = static_cast<const char *>(lv); |
| const char *r = static_cast<const char *>(rv); |
| return (*l != *r) || cmp(l + 1, r + 1, s - 1); |
| } |
| |
| template <int (*cmp)(const char *l, const char *r)> |
| static inline int fastcmp(const char *l, const char *r) { |
| return (*l != *r) || cmp(l + 1, r + 1); |
| } |
| |
| #endif |
| |
| #endif // _ANDROID_UTILS_FASTSTRCMP_H__ |